Metal oxide substrate (MOS) transistors that are fabricated using double diffusion layers may be used in integrated circuit applications with high power requirements. In particular, double diffusion metal oxide substrate (DMOS) transistors are useful because of their ability to have a large OFF state blocking voltage (BV.sub.dss). A large OFF state blocking voltage is useful in power applications to protect the transistor from the effects of surge voltages, such as from switching transients.
Nevertheless, increasing the OFF state blocking voltage for conventional DMOS devices usually includes changes to manufacturing process steps in the transistor fabrication process. These manufacturing process steps are commonly shared with non-DMOS components. Therefore, changes to the manufacturing process steps for manufacturing DMOS components may affect the non-DMOS components and cause significant problems with the construction and operation of these non-DMOS components.
In addition, adding manufacturing process steps to the manufacturing processes for such devices increases the manufacturing cost. Additional costs may also be incurred in resolving any problems that may be caused with the construction and operation of the non-DMOS components. These additional costs may cause the cost of producing integrated circuit packages containing DMOS components with large OFF state blocking voltages to be prohibitive.